An openly gay Australian lawmaker proposed to his long-term partner from the floor of federal parliament on Monday, shortly after a same-sex marriage bill was introduced to the House of Representatives.

Tim Wilson, a lawmaker with the ruling conservative Liberal Party, has been engaged to his partner for nine years and fought back tears as he repeated his proposal during a speech.

"In my first speech I defined our bond by the ring that sits on both of our left hands. They are the answer to the question we cannot ask," Wilson, 37, said as he looked to his partner sitting in the public gallery.

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"So there's only one thing left to do. Ryan Patrick Bolger, will you marry me?"

Bolger, 33, quickly answered yes, followed by applause from the House and public gallery.

"We'll chuck that in the memoirs and Hansard!" Wilson said, referring to the official record of proceedings and debates in parliament.

Results from a nation-wide, voluntary postal survey, released in November, showed an overwhelming majority of Australians supports changing the law to allow same-sex couples to marry.

Since then, politicians have been debating the issue, with a private-member's bill easily passing in the Senate last week.

Same-sex marriage legislation was introduced to the lower house on Monday morning and is expected to pass before the Christmas break.